Although Mike Singletary succeeded beyond all reasonable expectations in his role as interim head coach of the 49ers for the final nine games of 2008, he is still considered a rookie head coach in the NFL.

"Obviously, that's the appropriate term, my first year as head coach," he said in a quiet moment several days before the grindstone of training camp begins to turn later this week.

"I'm very excited. Very excited, very thankful that I have the coaching staff that we have. I'm thankful we have the staff set. We have a lot of good people in place. I'm very excited for our players, that we're going to take steps to achieve what we want to achieve. Very excited for all those things."

If nothing else, the 49ers open camp with a roster full of continuity. Minus training-camp surprises and injuries, 19 of the 22 starting scrimmage positions are settled before the first whistle has sounded. Counting kicker, punter, long snapper and return specialist, the 49ers have 23 of 26 starting jobs resolved going into camp.

That's a remarkable number for a team that not only had a losing record in 2008 (7-9) but is coming off six straight losing seasons.

However, the players believe continuity will contribute to success in 2009, as expressed by linebacker Takeo Spikes, who teams so well with Patrick Willis on the inside.

"Whenever you're able to keep the team together, it adds stability," said Spikes, noting the 49ers have extended the contracts of several players of late. "If you want a cohesive group of people, you have to have stability. As an incentive for players, you would like to think if you did what needs to be done in a three-year time period, you will be rewarded."

That plays well with the belief Singletary instilled in his players as he crafted a 5-4 record in his role as interim coach. As a result, the players believe their particular whole is greater than the sum of its parts.

"I think we brought in some guys that are going to help us," said quarterback Shaun Hill, referring to such additions as wide receiver Michael Crabtree, running back Glen Coffee and tackle Marvel Smith. "The guys who were here are better than they were a year ago. I think we're a much improved offense."

Going into camp, the only unsettled positions are quarterback, right tackle and right cornerback. All will play out in August practices and the first three exhibition games.

Quarterback is the focal point, of course. Much more scrutiny will be paid to Hill and Alex Smith as their duel plays out than Adam Snyder and Smith battling at right tackle or Dre' Bly and Tarell Brown competing for the right cornerback job.

Also to be determined is which wide receivers will play, and how much. Isaac Bruce and Josh Morgan figure to go into camp as the two starters, but everything else about the receiving corps is unsettled.

Top draft pick Crabtree has to be signed, first of all. As of Friday, he had not signed. Neither had running back Glen Coffee. Rookies are due to report Tuesday, with veterans coming in Thursday. The first practice is Saturday morning, setting off the busy month of August.

The 49ers will be in Napa on the 18th and 19th for four practice sessions against the Raiders, whom they play at Candlestick Park Aug. 22 By that point in camp, both teams will be grateful for someone in another color uniform to hit.

And when it comes to hitting, no one does it better than Willis, that tackling machine. Along with his mates on that side of the ball, Willis believes the 49ers have the makings of a top 10 defense.

"No doubt in my mind," he said. "I say it with confidence. Not only can we be a top-10 defense, we can be a top-five defense."

That would certainly please his head coach, who knows a thing or two about defense. Now is the time for him to show it.